反了，是先知道 $\displaystyle \exp(x) = \sum_{i=0}^{\infty} \frac{x^i}{i!}$，再定义 $e = \exp(1)$ 的
by 小粉兔 @ 2019-12-11 14:56:41
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by 1saunoya @ 2019-12-11 15:08:13
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by 基地A_I @ 2019-12-11 15:45:24
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by Siyuan @ 2019-12-11 15:50:43